The invention relates to a method and apparatus for the cold starting control of fuel injection systems, especially when used at very low temperatures.
In known fuel injection systems for internal combustion engines, a supplementary quantity of fuel is introduced during the starting and prior to and during the engine motion due to combustion. Such a supplementary fuel quantity is required because, in a cold engine, a large portion of the introduced fuel condenses on the walls of cold induction tubes, cylinders and pistons and thus prevents the formation of a combustible fuel-air mixture. The lower the engine temperature is during start-up, the more pronounced this problem becomes.
For this reason, a known fuel injection system includes a separate cold-start valve, located in the induction tube, which acts in addition to the normally present fuel injections valves. During starting temperatures below 20.degree. C., the cold starting valve supplies additional fuel to the engine and its operation is controlled by a thermal switch.
It is also conceivable to provide a fuel injection system which includes additional sensors for various engine variables and to transmit these signals from the sensors to various portions of the control circuit of the fuel injection system so as to permit a cold starting injection program. However, the engine conditions during cold starting are very complicated and make such a procedure unsuitable. Furthermore, a successful cold starting is not possible at very low temperatures.